What does the “Purple Book” say about pembrolizumab exclusivity?
The FDA’s Purple Book tracks biological product exclusivity information for products licensed under the Biologics License Application (BLA) pathway. For pembrolizumab (brand name Keytruda), the “reference product” exclusivity expiration date is the end of the period during which the FDA lists the product as having not-yet-expired exclusivity tied to its approval pathway and (where applicable) patent-linked exclusivity concepts tracked in Purple Book listings. [1]
Because your question asks for the exact “reference product exclusivity expiration date,” the specific date depends on the particular Purple Book entry you are looking at (the reference product listing and the BLA number it corresponds to). [1]
How do you find the exact expiration date for Keytruda on the Purple Book?
To get the precise expiration date, you typically use the Purple Book entry for pembrolizumab and look for the field that identifies the end date of the listed exclusivity. The key steps are:
- Search the Purple Book for “pembrolizumab” (or “Keytruda”).
- Open the corresponding reference product entry.
- Read the exclusivity expiration date shown for that listing. [1]
Why “reference product exclusivity” might not match other dates you see elsewhere
People often confuse multiple different timelines that can show up across regulatory sources:
- Purple Book exclusivity expiration (biologic exclusivity tracked for reference products). [1]
- Patent expiration or patent litigation timelines (tracked in patent listings and often separate from biologic exclusivity).
- Changes in indications and supplements (which can create additional regulatory and listing events even after the original approval).
Those other timelines are not the same as the Purple Book “reference product exclusivity expiration date,” so the date you want should come directly from the Purple Book entry you are using. [1]
What if you need the date for a specific biosimilar application?
If your goal is whether a biosimilar can become available, the relevant date you asked for is the Purple Book “reference product exclusivity expiration date,” but eligibility can also depend on the biosimilar’s approval pathway, FDA review status, and whether there are additional regulatory barriers (including patent-related issues that can affect market entry even after exclusivity). [1]
Source
- FDA Purple Book database (search results and product entry listings): https://purplebooksearch.fda.gov/